'use strict';

// Regular Expressions for parsing tags and attributes
var startTag = /^<([-A-Za-z0-9_]+)((?:\s+[a-zA-Z_:][-a-zA-Z0-9_:.]*(?:\s*=\s*(?:(?:"[^"]*")|(?:'[^']*')|[^>\s]+))?)*)\s*(\/?)>/,
  endTag = /^<\/([-A-Za-z0-9_]+)[^>]*>/,
  attr = /([a-zA-Z_:][-a-zA-Z0-9_:.]*)(?:\s*=\s*(?:(?:"((?:\\.|[^"])*)")|(?:'((?:\\.|[^'])*)')|([^>\s]+)))?/g;

// Empty Elements - HTML 5
var empty = makeMap("area,base,basefont,br,col,frame,hr,img,input,link,meta,param,embed,command,keygen,source,track,wbr");

// Block Elements - HTML 5
var block = makeMap("a,address,article,applet,aside,audio,blockquote,button,canvas,center,dd,del,dir,div,dl,dt,fieldset,figcaption,figure,footer,form,frameset,h1,h2,h3,h4,h5,h6,header,hgroup,hr,iframe,ins,isindex,li,map,menu,noframes,noscript,object,ol,output,p,pre,section,script,table,tbody,td,tfoot,th,thead,tr,ul,video");

// Inline Elements - HTML 5
var inline = makeMap("abbr,acronym,applet,b,basefont,bdo,big,br,button,cite,code,del,dfn,em,font,i,iframe,img,input,ins,kbd,label,map,object,q,s,samp,script,select,small,span,strike,strong,sub,sup,textarea,tt,u,var");

// Elements that you can, intentionally, leave open
// (and which close themselves)
var closeSelf = makeMap("colgroup,dd,dt,li,options,p,td,tfoot,th,thead,tr");

// Attributes that have their values filled in disabled="disabled"
var fillAttrs = makeMap("checked,compact,declare,defer,disabled,ismap,multiple,nohref,noresize,noshade,nowrap,readonly,selected");

// Special Elements (can contain anything)
var special = makeMap("script,style");

export const HTMLParser = function (html, handler) {
  var index, chars, match, stack = [], last = html;
  stack.last = function () {
    return this[this.length - 1];
  };

  while (html) {
    chars = true;

    // Make sure we're not in a script or style element
    if (!stack.last() || !special[stack.last()]) {

      // Comment
      if (html.indexOf("<!--") == 0) {
        index = html.indexOf("-->");

        if (index >= 0) {
          if (handler.comment)
            handler.comment(html.substring(4, index));
          html = html.substring(index + 3);
          chars = false;
        }

        // end tag
      } else if (html.indexOf("</") == 0) {
        match = html.match(endTag);

        if (match) {
          html = html.substring(match[0].length);
          match[0].replace(endTag, parseEndTag);
          chars = false;
        }

        // start tag
      } else if (html.indexOf("<") == 0) {
        match = html.match(startTag);

        if (match) {
          html = html.substring(match[0].length);
          match[0].replace(startTag, parseStartTag);
          chars = false;
        }
      }

      if (chars) {
        index = html.indexOf("<");

        var text = index < 0 ? html : html.substring(0, index);
        html = index < 0 ? "" : html.substring(index);

        if (handler.chars)
          handler.chars(text);
      }

    } else {
      html = html.replace(new RegExp("([\\s\\S]*?)<\/" + stack.last() + "[^>]*>"), function (all, text) {
        text = text.replace(/<!--([\s\S]*?)-->|<!\[CDATA\[([\s\S]*?)]]>/g, "$1$2");
        if (handler.chars)
          handler.chars(text);

        return "";
      });

      parseEndTag("", stack.last());
    }

    if (html == last)
      throw "Parse Error: " + html;
    last = html;
  }

  // Clean up any remaining tags
  parseEndTag();

  function parseStartTag(tag, tagName, rest, unary) {
    tagName = tagName.toLowerCase();

    if (block[tagName]) {
      while (stack.last() && inline[stack.last()]) {
        parseEndTag("", stack.last());
      }
    }

    if (closeSelf[tagName] && stack.last() == tagName) {
      parseEndTag("", tagName);
    }

    unary = empty[tagName] || !!unary;

    if (!unary)
      stack.push(tagName);

    if (handler.start) {
      var attrs = [];

      rest.replace(attr, function (match, name) {
        var value = arguments[2] ? arguments[2] :
          arguments[3] ? arguments[3] :
            arguments[4] ? arguments[4] :
              fillAttrs[name] ? name : "";

        attrs.push({
          name: name,
          value: value,
          escaped: value.replace(/(^|[^\\])"/g, '$1\\\"') //"
        });
      });

      if (handler.start)
        handler.start(tagName, attrs, unary);
    }
  }

  function parseEndTag(tag, tagName) {
    // If no tag name is provided, clean shop
    if (!tagName)
      var pos = 0;

    // Find the closest opened tag of the same type
    else
      for (var pos = stack.length - 1; pos >= 0; pos--)
        if (stack[pos] == tagName)
          break;

    if (pos >= 0) {
      // Close all the open elements, up the stack
      for (var i = stack.length - 1; i >= pos; i--)
        if (handler.end)
          handler.end(stack[i]);

      // Remove the open elements from the stack
      stack.length = pos;
    }
  }
};

export const HTMLtoXML = function (html) {
  var results = "";

  HTMLParser(html, {
    start: function (tag, attrs, unary) {
      results += "<" + tag;

      for (var i = 0; i < attrs.length; i++)
        results += " " + attrs[i].name + '="' + attrs[i].escaped + '"';
      results += ">";
    },
    end: function (tag) {
      results += "</" + tag + ">";
    },
    chars: function (text) {
      results += text;
    },
    comment: function (text) {
      results += "<!--" + text + "-->";
    }
  });

  return results;
};

export const HTMLtoDOM = function (html, doc) {
  // There can be only one of these elements
  var one = makeMap("html,head,body,title");

  // Enforce a structure for the document
  var structure = {
    link: "head",
    base: "head"
  };

  if (!doc) {
    if (typeof DOMDocument != "undefined")
      doc = new DOMDocument();
    else if (typeof document != "undefined" && document.implementation && document.implementation.createDocument)
      doc = document.implementation.createDocument("", "", null);
    else if (typeof ActiveX != "undefined")
      doc = new ActiveXObject("Msxml.DOMDocument");

  } else
    doc = doc.ownerDocument ||
      doc.getOwnerDocument && doc.getOwnerDocument() ||
      doc;

  var elems = [],
    documentElement = doc.documentElement ||
      doc.getDocumentElement && doc.getDocumentElement();

  // If we're dealing with an empty document then we
  // need to pre-populate it with the HTML document structure
  if (!documentElement && doc.createElement) (function () {
    var html = doc.createElement("html");
    var head = doc.createElement("head");
    head.appendChild(doc.createElement("title"));
    html.appendChild(head);
    html.appendChild(doc.createElement("body"));
    doc.appendChild(html);
  })();

  // Find all the unique elements
  if (doc.getElementsByTagName)
    for (var i in one)
      one[i] = doc.getElementsByTagName(i)[0];

  // If we're working with a document, inject contents into
  // the body element
  var curParentNode = one.body;

  HTMLParser(html, {
    start: function (tagName, attrs, unary) {
      // If it's a pre-built element, then we can ignore
      // its construction
      if (one[tagName]) {
        curParentNode = one[tagName];
        if (!unary) {
          elems.push(curParentNode);
        }
        return;
      }

      var elem = doc.createElement(tagName);

      for (var attr in attrs)
        elem.setAttribute(attrs[attr].name, attrs[attr].value);

      if (structure[tagName] && typeof one[structure[tagName]] != "boolean")
        one[structure[tagName]].appendChild(elem);

      else if (curParentNode && curParentNode.appendChild)
        curParentNode.appendChild(elem);

      if (!unary) {
        elems.push(elem);
        curParentNode = elem;
      }
    },
    end: function (tag) {
      elems.length -= 1;

      // Init the new parentNode
      curParentNode = elems[elems.length - 1];
    },
    chars: function (text) {
      curParentNode.appendChild(doc.createTextNode(text));
    },
    comment: function (text) {
      // create comment node
    }
  });

  return doc;
};

function makeMap(str) {
  var obj = {}, items = str.split(",");
  for (var i = 0; i < items.length; i++)
    obj[items[i]] = true;
  return obj;
}
